The era of expatriate officers in the 173-year history of the Hong Kong Police Force is expected to end in a decade as the last serving overseas staff call time on their careers.

The 30,000-strong force will see the number of serving expat police fall to just 60 by the end of next year after decades of domination by colonial administrators.

Some retired colonial officers and policing experts said it was sad to see their numbers slump, as they had played a significant part in the city’s history, but the sunset was “inevitable”.

According to official figures, there were 82 serving expat officers as of September 1, ranging from inspectors to assistant commissioner.

“Since the beginning of 2017, 10 officers have already retired and seven more will retire in the coming months, making this year the retirement peak for the serving officers on overseas agreement terms,” a police spokeswoman said.

She added that 15 more officers were expected to retire from the thin blue line next year.

At their peak around 1990, there were an estimated 900 overseas officers serving in Hong Kong.

Superintendent Timothy Worrall, 44, is among the last batch recruited by the force in 1994. He is the youngest serving foreign officer and is expected to retire in January 2028.

Watch: Hong Kong’s youngest expatriate police officer

“I do not give much thought to my being the last overseas officer as there are many more things I would like to achieve in the time I have left with the force,” said the Briton, who is commander of the police’s small boat division.

The force stopped hiring from overseas in 1994 and introduced Chinese-language requirements, including in reading, writing and speaking.

More than 10 ethnic minority recruits have joined in recent years with Pakistani, Indian, Nepalese and Filipino backgrounds, but they were hired on local contract terms and passed the language tests.

In Worrall’s eyes, foreign and local policemen are no different in terms of their capabilities.

“Overseas recruitment provided the force with a diverse make-up of officers, which was an advantage in the policing of an international cosmopolitan city,” Worrall said.

“Today, officers come from a wide range of cultural, ethnic and educational backgrounds. The diversification that you used to get from recruiting officers overseas, you can get it in Hong Kong. If you get the right people at home, why not recruit them locally?”

The benefits afforded expatriate officers on overseas contract terms are slightly different to those for local officers, with the former generally receiving more than HK$20,000 as a passage allowance annually and extra leave to visit family back home.

Former deputy commissioner Keith Lomas, who is the chairman of the Royal Hong Kong Police Association, which represents 920 ex-officers, said the changes were “inevitable”.

When asked if he thought the force should resume overseas recruitment, he said: “No, not really. Circumstances, and in particular the political background, have changed.”

Lomas joined the force in 1957 after compulsory national service with Britain’s Royal Air Force in Malaysia on helicopters.

“There may occasionally be expatriate officers after that but only those with specialised knowledge to provide training,” he said.

He retired in 1994 and returned to Britain primarily for his two daughters.

“Bearing in mind the coming change of sovereignty and the political uncertainty as to what that would entail, I wanted a secure place for them,” Lomas said.

Alexander Threadgill left the Royal Hong Kong Police in 1995 after 11 years. He said he found the sun setting on the era of overseas officers “rather a shame but inevitable”.

“In my experience, the European, Chinese and Pakistani officers for the most part worked very well together. Each group had strengths and weaknesses, but they complemented each other,” said the Briton, who now works for a software production company back home.

Brett Williams, another Briton, abandoned his plan in 1977 to join the British army in favour of a career with the Hong Kong police. He said many officers worldwide would like to serve in Hong Kong and the city might benefit from their expertise.

“Perhaps not as a full-time career but on, say, two to five-year contracts in certain fields,” Williams, who served between 1977 and 1997, said. He left his position as chief inspector at the handover to migrate to Australia, and now runs a business there selling hand-painted statues.

“For example, perhaps someone from the London Metropolitan Police Service who has experience in counterterrorism from a different perspective,” he said.

Lawrence Ho Ka-ki, an expert on the history of Hong Kong policing and assistant professor at the Education University of Hong Kong’s department of social sciences, said the force hired more overseas police officers after the second world war as the colonial government did not trust Chinese recruits and many locals did not want to join anyway.

But with the expansion of the police and growing localism in the 1970s, more Hongkongers signed up for service.

“Expatriate officers took a role in the institutionalisation and professionalisation of the force,” Ho said. “The British military trained the Police Tactical Unit when it was established and infused the unit with their own anti-riot tactics. The experience of policing in different Commonwealth countries also helped with drafting the Police General Orders.”

Ho said overseas police officers could serve as consultants or trainers in future, but being a fully paid-up member of the force was unlikely.